The bowl doesn’t get clean when I flush.

Before you begin the steps to determine what caused the problem, it is essential that the bowl is clean. This may mean that you have to flush a few times or, if your toilet is completely clogged, you may need to plunge.
Important: Do not continue to the next step until the bowl is clean. If you're having trouble getting the bowl clean, you may need to consult a plumber.

Due to changes in the water pressure, it may be necessary to adjust the flush valve to ensure that the toilet is using 1.6 gallons per flush. If you've got a flush valve float, lower it slightly (one or two beads).

Make sure the chain has only 1/4 inch of slack. (When you hit the trip lever, the arm should only move 1/4 inch before activation.)

Use a mirror and a coat hanger or a 6/8 penny nail to clean out the holes under the rim (inside the bowl).
Mineral deposits from water may cause the rim holes and jet hole to "shrink," which limits the flow of water.

If there is a jet hole, use a screwdriver to clean it out.
Important: Do not stick your finger in the jet hole.

Flush.

Make sure the rim holes and jet hole (if applicable) are completely clean.